In general, contemporary on-chip measurement circuits have a crude accuracy limited by a timing through a single inverter chain. The timing through the single inverter chain comprises a propagation time from one latch to the next latch when performing measurements. The crude accuracy results from picosecond resolution of the propagation time, which can be on the order of 5 to 8 picoseconds.
An attempt to address this crude accuracy includes modifying an on-chip measurement internal voltage in steps of approximately 1 mV to provide a precise timing measurement solution. However, this is only a viable solution for power noise measurements when the on-chip measurement internal voltage is what needs to be measured. In all other scenarios, modifying the on-chip measurement internal voltage is not a viable option because it is not possible to change a processor voltage for measurement purposes (e.g. in a customer environment).
At present, there is a need for alternative precise timing measurement solutions to address the crude accuracy of the contemporary on-chip measurement circuits.